This application is a continuation-in-part of prior copending U.S. application Ser. No. 838,283 filed Mar. 10, 1986, now U.S. Pat. No. 4,85 for Fiber Optic Probe System, the disclosure of which is incorporated herein by reference and the benefit of the filing date is claimed herefor.
In recent years efforts have been made to develop fiber optic technology for various purposes including the use of a bent fiber optic refractometer device for measurement of salinity in double diffusive thermohaline systems as described in Rev. Sci. Instrum. 56(2), February 1985 of the American Institute of Physics, the disclosure of which is incorporated herein by reference. Powell U.S. Pat. No. 4,256,403, the disclosure of which is incorporated herein by reference, discloses a water contaminate and fuel density detector using a longitudinally extending body of light transmitting material with light emitting means at one end to provide a group of divergent rays in angularly disposed light emission paths onto a plurality of vertically spaced light sensors for producing a signal corresponding to the index of refraction indicating the density of the fuel, while also indicating the presence of water in the fuel.
In general, the present invention utilizes a sheathed and/or coated optical fiber means having a first sheathed and/or coated light path portion connected to a light emitting device for transmitting light from the light emitting device along a first covered light transmission path, an intermediate, unsheathed, exposed core portion having an abraded peripheral surface for providing a sensor means, and a second sheathed and/or coated path portion connected to a light receiving device for receiving transmitted light from the light source and generating variable output signals dependent on characteristics of received light. The optical fiber device is constructed and arranged to prevent light loss in the first path portion and the second path portion with variable light losses occurring in the intermediate portion depending upon variations in environmental conditions at the intermediate portion. The variable light losses in the intermediate portion are dependent on the reflection and refraction and absorbtion characteristics of the intermediate portion of the optical fiber device and the reflection and refraction and absorption characteristics of the environmental medium in contact with the intermediate portion. Since various characteristics, such as reflection, refraction, heat of fusion, rate of temperature change in various phases, etc., of various mediums, such as air, water, ice, corn oil, gasoline, etc., are known or can be determined, the amount of light loss in the intermediate portion can be calculated with respect to various surrounding mediums. Differences in the amount of light received by the light measuring device can be used to indicate the nature or phase (i.e., solid, liquid, gaseous) of the environmental medium in contact with an outer surface of the intermediate portion of the optical fiber device.